60 SOILS AND FERTILIZERS 



weights of the two portions of soil in respective lamp chimneys, 

 having previously tied cheesecloth neatly over the bottoms to keep 

 the soil in place and yet to allow drainag3. Compact the soils to 

 uniform height. Weigh each chimney plus its portion of soil. 

 Set the chimneys in such a position as to allow free drainage. Pour 

 equal amounts of water on each and observe the rate of percolation 

 of the water through the two soils. Explain results and show the 

 practical bearing of the experiment. 



Exercise VI. — Influence of organic matter on percentage of 

 moisture held in soil. 



Materials. — Same as Exercise V. 



Procedure. — After observing the rate of percolation in the 

 above exercise, saturate the soils, and allow them to drain freely 

 until all gravity water has disappeared. Now weigh each chimney 

 plus its soil. The increased weight over that of the original sample 

 is water retained. Calculate the percentage of water thus re- 

 tained, based on the weight of the original dry sample. Explain 

 the practical importance of the results. 



